DirectShow内存无法正常释放

Question

我使用directshow时遇到了内存问题，更具体地说，是directshow.net库

目标是复制AVI文件并且一切正常，除了在调用Marshal.ReleaseComObject之后内存根本不释放的事实。

我正在创建图表的几个步骤

1. 创建IFilterGraph2对象
2. 创建ICaptureGraphBuilder2
3. 设置Filtergraph
4. 使用IFilterGraph2.AddSourceFilter
添加源过滤器
5. 创建和配置ISampleGrabber
6. 添加ISampleGrabber
7. 渲染流

此时，如果我从图表中删除过滤器并调用ISampleGrabber，IFilterGraph2和ICaptureGraphBuilder2上的Marshal.ReleaseComObject来释放，则内存仍然保留并且永不卸载。

问题是，如果我在不关闭整个过程的情况下播放很多文件，我最终会收到来自Com Objects的80004001错误，这听起来有点奇怪

提前感谢阅读和任何进一步的建议

编辑：从directshow.net库示例添加代码，该代码具有相同的行为

    private void SetupGraph(Control hWin, string FileName)
    {
        int hr;

        // Get the graphbuilder object
        m_FilterGraph = new FilterGraph() as IFilterGraph2;

        // Get a ICaptureGraphBuilder2 to help build the graph
        ICaptureGraphBuilder2 icgb2 = new CaptureGraphBuilder2() as ICaptureGraphBuilder2;

        try
        {
            // Link the ICaptureGraphBuilder2 to the IFilterGraph2
            hr = icgb2.SetFiltergraph(m_FilterGraph);
            DsError.ThrowExceptionForHR( hr );


            // Add the filters necessary to render the file.  This function will
            // work with a number of different file types.
            IBaseFilter sourceFilter = null;
            hr = m_FilterGraph.AddSourceFilter(FileName, FileName, out sourceFilter);
            DsError.ThrowExceptionForHR( hr );

            // Get the SampleGrabber interface
            m_sampGrabber = (ISampleGrabber) new SampleGrabber();
            IBaseFilter baseGrabFlt = (IBaseFilter) m_sampGrabber;

            // Configure the Sample Grabber
            ConfigureSampleGrabber(m_sampGrabber);

            // Add it to the filter
            hr = m_FilterGraph.AddFilter( baseGrabFlt, "Ds.NET Grabber" );
            DsError.ThrowExceptionForHR( hr );

            // Connect the pieces together, use the default renderer
            hr = icgb2.RenderStream(null, null, sourceFilter, baseGrabFlt, null);
            DsError.ThrowExceptionForHR( hr );

            // Now that the graph is built, read the dimensions of the bitmaps we'll be getting
            SaveSizeInfo(m_sampGrabber);

            // Configure the Video Window
            IVideoWindow videoWindow = m_FilterGraph as IVideoWindow;
            ConfigureVideoWindow(videoWindow, hWin);

            // Grab some other interfaces
            m_mediaEvent = m_FilterGraph as IMediaEvent;
            m_mediaCtrl = m_FilterGraph as IMediaControl;
        }
        finally
        {
            if (icgb2 != null)
            {
                Marshal.ReleaseComObject(icgb2);
                icgb2 = null;
            }
        }

    }